Fluid machine



Oct. zo, 1936. A. HOLLANDER FLUID MACHINE Filed April 15, 1935 @Ruim INVENTOR.

G14/KVS ATTORNEYS l ,Patented Oct. 20, 1936 UNITED s'rTEs FLUID MACHINE u snaar nellenaer, Berkeley, cem.. assignee te Byron Jackson Co., Berkeley, Calif., a corporation of Delaware Applicaties spell 1s, loss, serial No. 16,172 i iclslm.. (ci. s-los) t l locking. f

yOther objects and advantagesv of the invention will become apparent as the nature of the same is more fully understood from the following description and accompanying drawing, wherein is set forth what is now considered to be a preferred embodiment. It should beunderstood, however,

that this particular e ent of the invention is chosen principally for the vvurpose of exempliiication and that variations herefrom in details of construction or arrangement of parts may accordingly be effected' and yet `remain within I4the g5 spirit and scope of the invention as the sameis l set forth in the appended claim. Tfhe drawing illustrates a vertical cross-sectional view throughfthe shaft 'axis of a. double l casing, -multi-stage, centrifugal pump'employing my invention. l s

One of the problems met with-in a high speed; double casing pump is the formation of vapor in the suction passages leading'into the inlet eye oi the rst stage impeller when pumping volatile .35 fluidssuch as hot oil, hot feed water for boilers or inherently volatile fluids such as butane. i The formationofvapor in/the suction passages dele-l teriously affects theoperating characteristics of the machine and `therefore should bel eliminated 40 vif possible. A V

In the ordinary pumps of this character, the formationof vapor in' the suction passages is due largely to their necessarily restricted size and therefore the suction :duid must travel at a. very high velocity in order to' keep pace .with suction created by the first stage impeller-and as a result' thereof. if the suction fluid can not flow into the first stage impeller with sufficient speed to satisfy its demand, a reduction of pressure Vor partial 50. vacuum will be created in the inlet eye of, this impeller. As will be appreciated when pumping highly volatile iluids, a slightV reduction in pressure will in many cases cause vapor to develop inthe iluid and` thus impair the operating efficiency of the machine. l

After considerable experimentation, I have discovered a simple and effective method of correcting this fault, which method resides in providing the machine with a double suction4 first stage impeller whereby thesuctionpassages may have 5 substantially twice the eiective area'and thus practically reducing the velocity of the inowing fluid to one-half. As a result thereof. vaporization of the suction fluid is substantially eliminated. 10 Heretofore it has been thought impossible to4 provide a double casing pump with a double suction first stage impeller, due to the difficulty of providing a suction fluid passage to the inner inlet eyeI of this impeller. This difficulty I have ef- 15 fectively overcome by the arrangement of the suction and pressure chambers formed between the two casings of the machine and by placing the double suction impeller within the suction chamber. andthereby making possible a vshort '20 direct suction passage of relatively large area each side of this impeller, whereby the infiowing fluid' may now smoothly and easily into the two suction inlet eyes of the first stage double suction impeller. y

The double casing multi-stage centrifugal pump having a double suction rst stage impeller as illustrated in th'e drawing, may include an outer or pressure casing i, which will be referred to as the housing in order to distinguish it from the 30 inner'or impeller casing 2. Theborepf the housing may be divided into a suctionarea 4 and a pressure area 3 separated by a'shoulder seat 5.' 'I'he suction area l is shown of less diameter than the diameter of the pressure area 3 in order to 35' provide the radial seating shoulder 6 but it is to be understoodthat any'other'arrang'ement may be provided which will provide a suction area and a pressure area separated `by a suitable form of seat.

In the machine shown, the housing is provided 40 with an integrally cast suction end 6 but a separateend bolted on may. be used if preferred. The s pressure end of the housing is provided with a flange 'I to which the end cover ljmay be securely fastnedvas by bolt means 9. The housing is pro- 45 vided with a suction nozzle Ill having -a suction passage Il forcommunicating the suction area l' with the exterior of the housing and a discharge nozzle I2 provided with a discharge passage il for communicating the pressure area with the exterior. V l The impeller casing 2 is generally cylindrical in exterior form, having a suction area i4 of a diameter less than the diameter of the suction` area of the housing bore so as to provide therebetween 55 a suction chamber I 8, while the pressure area I8 shoulder seat II arranged to cooperate with housing seat 5 vto form therewith an eifective fluid seal. The pressure area I8 of the casing is of less diameter than the diameter of the housing pressure area '3 so as to form therebetween a pressure chamber I8.

When the casing is mounted within the housing as shown in the drawing, the respective seats I1 and 54 are maintained in sealing engagement by the resilient gasket I9 acting between cover 8 and the adjacent end of the casing when the machine is not in operation and by this gasket plus the pressure difference between the suction and pressure chambers, which acts .to drive the inner casing seat with considera; force against the housing seat, when the pump is in operation.

The suction end of the casing is provided with a double suction impeller cavity I2li which in the machine shown is within the suction area I5 -thereof but may be differently located, if preferred. The casing is provided with twelve single suction impeller cavities 2I all located within the pressure area. An impeller shaft 22 extends axially through the housing and casing and is prvided with a double suction impeller 23 for the double suction cavity and a single suction impeller 24 for each of the single suction formed in the casing.

The customary stuillng boxes and bearing are provided for the shaft and the impellers are mounted thereon in the usual manner and therefore need not be described in detail. The number and arrangement of single suction impellers may be varied to suit any particular condition for which the machine may be made tooperate.

The important diierence between this pump and other double casing pumps is the inclusion of a double suction first stage impeller and the manner of. providing suction passages to each side thereof. It will be noted that the first stage double suctionimpeller is spaced from its nearest single suction impeller in order to provide sufflcient room for the inlet passage 25, which passage is of relatively large area and communicates the inwardly directed inlet eye of the double suction impeller with the suction chamber I5. The double suction impeller cavity is also spaced a suilicient distance from the end of the casing to enable the provision of a relativelylarge inlet passage 26 to communicate the other inlet eye of the double suction impeller with the suction chamber. In this machine, the suction chamber is made vof suiiicient size to permit the suction passage II to be of relatively large area as compared with the area of the discharge passage I3' and likewise to provide large and streamlined inlet passages 25-26 to the opposite sides of the double suction impeller whereby the suction fluidmay flow into the double suction impeller in a relatively leisurely manner along well formed streamlined passages and as a result thereof, the tendency of the fluid under treatment to vaporize Will be substantially eliminated.

A iluid passage 21 receives the uid discharged cavities from the first stage impeller cavity and conveys it serially through each of the single suction impeller cavities and finally dischargesfthe fluid into the pressure chamber I8 from which it may be discharged through passage outlet I3.

It will be understood'that the impeller casing is parted in a plane perpendicular to that shown in the drawing, whereby the shaft and impellers may be mounted therein.

As shown in this embodiment, the first stage double suctionv impeller and cavity are smaller in diameter than the single suction impellers and cavities in order that the suction area of the casing may be reduced in diameter to provide the shoulder seat I'I. However, it is to be understood that all of the impellers and cavities may be of the same diameter and the pressure area increased slightly in diameter to provide a suitable seat, but the construction shown is preferred.

Thev preference to the shown construction, wherein the lfirst stage double suction impeller and cavity therefor are of smaller diameter than the single suction impellers and cavities, is due to the provision of the seating shoulder I'i without necessitating an increase in the diameter of the pressure section of the impeller casing and therefore it is not necessary to increase the size of the housing which, due to the stress caused by the relatively high internal pressure, should be made as small in diameter as possible. Also, 'due to this arrangement, sufficient room is provided for the uid passage to traverse the impeller casing from the discharge of the rst stage impeller cavity to the inlet passage of the second stage impeller cavity.

Having fully described a preferred embodiment of the invention, it is to be understood that it is not to be limited to the details herein set forth, but the invention is for the full scope of the appended claim.

I claim:

In a double .casing multi-stage centrifugal pump, a housing vhaving longitudinally spaced suction and pressure areas separated by an annular seat and suction and pressure passages communicating their related suction and pressure areas with the exterior thereof, an impeller casing within said housing having longitudinally spaced suction and pressure areas separated by an annular seat which engages said housing annular seat, said casing having a plurality of Singlesuction impeller volutes formed in the pressure area and a double suction impeller volute formed in the suction area, an impeller shaft extending through said single and double suction impeller volutes, 'a double and a plurality of single suction impellers mounted upon said shaft for operation in their related volutes, said casing having a suction opening formed in its suction area and alined with said housing suction passage, fluid passages in said casing leading directly from said suction opening to the inlets of the double suction impeller, the discharge of the double suction impeller being led successively through the single suction impellers and finally discharging into the pressure chamber.

ALADAR HOLLANDER. 

